1. Technical Field
The present invention relates generally to the field of motor vehicle heating, ventilation, and air conditioning (HVAC) systems and to vehicle power train cooling (PTC) systems and more particularly to a hybrid thermal control system for vehicles.
2. Background Art
Although the traditional internal combustion engine is still the most widely accepted power plant for mainstream motor vehicles, other types of vehicles are making inroads into the consumer marketplace. For example, electric and hybrid electric vehicles are becoming increasingly popular for certain consumer segments. Similarly, fuel cell engines and high-efficiency diesel engines are also growing in popularity as attractive alternatives to the standard gasoline powered engine. As automakers seek to accommodate these various trends in consumer buying habits, the process of designing and manufacturing vehicles that incorporate these new engines is also changing.
For example, in order to meet the rapidly growing demand for electric vehicles, many automakers are seeking to “retrofit” existing internal combustion engine vehicle designs with electric engines. This process includes changing out the engine and related components as necessary to accommodate the change in propulsion systems. Obviously, the manufacturer would like to change as few components as necessary in order to minimize costs and reduce the amount of time that it takes to get a new electric powered vehicle into production. While many of the components can be the same, regardless of the type of engine, certain components may be removed or added when updating an existing vehicle design to accommodate a battery powered engine. One area where this is most noticeable is the HVAC system for the vehicle.
Specifically, while traditional internal combustions engines generate excess heat that can be used for the various heating needs of the vehicle, such as heating the passenger cabin during cooler weather, most electric vehicle engines do not generate much excess heat. Similarly, the cooling requirements for an electric vehicle are also different in that cooling may be provided for certain additional components such as the electric vehicle's batteries. In addition, since many electric vehicles utilize heat pumps, different HVAC components may be added to a vehicle when an electric engine is to be installed. This variation in heating and cooling requirements for different types of engines translates to additional design and manufacturing time as well as increased cost for introducing new vehicles into the marketplace. Accordingly, to the extent possible, manufacturers seek additional opportunities to quickly and efficiently update existing vehicle designs and to use existing subsystems to accommodate new and emerging engine technologies.
In view of the foregoing, it should be appreciated that it would be desirable to provide methods and apparatus for minimizing the amount of time and money required by automakers to re-design existing vehicles for new and emerging engine technologies. Specifically, the ability to minimize design changes can provide the manufacturer with manufacturing flexibility, increased production capacity and shorten time to market. In addition, a single thermal system, adaptable to meet all of a vehicle's thermal requirements, would be desirable. Furthermore, additional desirable features will become apparent to one skilled in the art from the foregoing background of the invention and following detailed description of a preferred exemplary embodiment and appended claims.